FWIW, I'm a similar age (54), get a decent amount of exercise, but have similar problems.

Finally this year went to the MD, and after an Xray & MRI, he discovered I have spondylolisthesis (mislocated vertebra).

Anyhow you may want to check further before just doing exercises, to find out if there's something structurally wrong, before you make it worse.

Just a thought.